6.2 Sample Size The primary end point of this phase II study is the objective tumor response rate. This study is a two-stage design for testing non-inferiority of the proposed treatment as compared to the approximately 80% response rate reported for conventional treatment. Assuming a non-inferiority margin of 20%, a sample size of 25 subjects, which provides an 80% power for establishment of non-inferiority, was selected based on the method described in Batchelor et al.7 At the first stage, 15 subjects are to be enrolled. If fewer than six patients respond (the one-sided 93% upper bound of the observed response rate is lower than 60%), the study would be terminated. Otherwise, the study would accrue additional 10 subjects. At the end of second stage, if the one-sided lower 95% confidence limit of the point estimate of the response rate is greater than or equal to 60%, the hypothesis that the study treatment is inferior to the conventional treatment would not be rejected.